This chapter is from the book

This chapter is from the book

Cleanliness is next to godliness, and without starting a religious debate,
I am sure you agree with me that the bane of all retouchers is dust, mold, moiré
patterns, print texture, and film grain. Removing these problems can be a time-consuming,
eye-straining, arm-numbing endeavor, all of which can really take the fun out
of digital retouching. In this chapter you'll face the worst problems and
learn the best techniques to rescue your images from the evils that lurk in
historical negatives, glass plates, prints, contemporary film, and digital images.

The problems tackled in this chapter include

Removing dust, mold, and scratches

Minimizing moiré patterns and paper texture

Reducing, maintaining, and matching film grain

The tools used to conquer these dusty and dirty challenges include

Layers and Blending Modes

The Clone Stamp tool

The Blur tool

Photoshop filters

The History palette and History Brush tool

So roll up your mousing sleeve and let's get to work.

Depending on the severity of the problem, there are numerous Photoshop techniques
to clean up dust and mold, many of which can be used interchangeably or in combination
with one another. My favorite technique is to avoid the problem in the first
place by cleaning the negative, print, or scanner before making the scan. By
carefully brushing or blowing off loose dust from a negative or print, you're
removing the source of the problem. Never rub film, prints, or scanner platens
very hard because you can scratch and permanently damage them.

Because there isn't one perfect method to remove dust specks or to reduce
mold damage, this chapter includes a variety of methods to tackle these problems.
Dust problems are most often seen as very small specs of dark or light pixels,
and mold damage looks mottled, patterned, or discolored and affects larger areas.
By experimenting with or combining methods, you'll develop techniques to
take care of your image's worst problems.

Dustbusting 101

An important concept to recognize is that there is no dust in a digital file.
The dust was on or in the original. In the digital file all you really have is
lighter or darker pixels in contrast to darker or lighter backgrounds. Taking
advantage of this concept can speed up your dustbusting sessions.

Using the Blur Tool

The Blur tool is especially useful on files that have a lot of small, random
dust specks on a variety of backgrounds. Over the years dust became embedded
in the original image shown in Figure 5.1.
After scanning, the myriad of small, dark specks makes the wall and the image
look dirty and unattractive. The Blur tool was used successfully to clean up
the image, as seen in Figure 5.2.

Activate the Blur tool and set its options to 100% Pressure and Use All
Layers as seen in Figure 5.3. To
eradicate light specks, set the Blur tool's Blending Mode to Darken;
to make dark specks disappear, set the Blending Mode to Lighten.

Figure
5.3 Set the Blur tool to 100% Pressure and Lighten Mode to remove dark
specks.

Zoom in to 100% or 200% view.

Set the Blur tool's size to approximately match the size of the dust
speck.

Click and hold the Blur tool over the dust spot (see Figure
5.4). The longer you hold down the mouse button, the more the dust will
be blurred into oblivion.

Figure
5.4 Hold down the Blur tool over the speck until it disappears.

NOTE

Be careful not to overblur the dust because that will soften the image area
so much that soft blobs will begin to appear. There is a fine balance between
just right and too much blurringwith a bit of practice you'll develop
an eye for the right amount of blurring.

TIP

Matching the size of the brush to the size of the dust speck to be removed
and using a hard-edged brush ensures that you don't soften the grain
of the image surrounding the dust speck. Use the keyboard shortcuts to control
the size of the brushes:

Left bracket ([) decreases brush size.

Right bracket (]) increases brush size.

Using the Shift key with either bracket adjusts the brush
hardness in 25% increments.

The Float and Move Technique

Use the float and move technique on unimportant image areas such as skies or
backgrounds to quickly disguise dust on large surfaces. Duplicating a
troublesome area with a slight offset and applying a Lighten Blending Mode is a
quick and easy way to remove many flaws. I first heard about this technique from
Stephen Johnson as he was retouching numerous glass plate negatives for his
book, "The Great Central Valley."

Figure 5.5 and Figure
5.6 show before and after detail of the identical file that was cleaned
up with the float and move technique. Notice how the dust and mold has been
minimized in the sidewalk and the sky. (Because I didn't float and move
any important image areas such as the buildings or people, they still have dust
and damage that will require individual attention later in the retouching process.)

Press V to select the Move tool and use the arrow keys to nudge the new
layer down and over to the right 23 pixels.

Change the moved layer's Blending Mode to Lighten to hide the dark
spots (see Figure 5.8).

Figure
5.8 After moving the new layer, change the Blending Mode to Lighten to
hide dust and mold.

A Professional Float and Move Example

Photographer John Warner used the float and move technique to repair the
lawn of a croquet field which had been aerated to promote lawn growth. John
needed to photograph the playing surface for a promotional brochure before
the grass had a chance to recover, as shown in Figure
5.9, so he used Photoshop to repair the lawn faster than Mother Nature
could have (see Figure 5.10).

John duplicated the Background layer and set the Blending Mode to Darken,
then named the layer Lawn Care.

He used the Move tool and the arrow keys to move the Darken layer several
pixels down until the white holes disappeared.

Duplicating and moving the entire layer also affected the cottages. To
bring the cottages back into focus, John added a layer mask by clicking
the Add Layer Mask icon on the Layers palette.

He used the Gradient tool to draw a black-to-white blend on the layer
mask to block the Darken Blending Mode from affecting the cottages and
upper part of the lawn, as seen in Figure
5.11.

Figure
5.11 A gradient will hide areas that you don't want affected with
a layer mask.

Finally, John cloned over any remaining white marks on the croquet lawn
to add the final polish to the image.

Controlling the Dust & Scratches Filter

The float and move technique works very well on unimportant image areas, such
as sky and studio backgrounds. As good as this technique is, it may also soften
important image texture or film grain. Use the following Dust & Scratches
filter technique whenever you need to maintain texture or film grain.

Figure 5.12 and Figure
5.13 show a before and after detail of the identical file that was cleaned
up with this Dust & Scratches filter technique. Notice how the numerous
dust specks and most of the mold has been removed from the sidewalk although
the film grain and sidewalk texture is still visible.